1632276 - support uint indexes in SWGL DrawElements

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, task, P3)

Description

[Lee Salzman [:lsalzman]]

To support the WR debug renderer and debug overlays in SWGL, we need to properly support supplying GL_UNSIGNED_INT-typed indexes to glDrawElements. The current hack just casts them directly to uint16, which can break if the indexes won't fit, plus has associated conversion cost to allocate an intermediate uint16 index array.

Since WR only ever supplies triangles in fixed index orders- 0,1,2 for triangle and 0,1,2,2,1,3 for quads - we can take advantage of this to not need to pass around index arrays. Instead, we can assume vertex attributes will always be supplied in those orders and just pass around the base index with offsets relative to that for successive vertexes.

Comment 1

[Lee Salzman [:lsalzman]]

Attachment: Bug 1632276 - support full-range unsigned int indexes in SWGL DrawElements. r?jimb

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5f0e442a51d2
support full-range unsigned int indexes in SWGL DrawElements. r=jimb

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/5f0e442a51d2